Interestingly, several genes whose precise molecular interactions are yet to be completely understood, are among the most highly expressed genes in both proximal and distal tumors including OTOP2 (controlled by wild-type TP53) [30], OTOP3, PYY and PPIAL4; and many with limited supporting evidence, might serve as interesting candidates for future research in colon cancers (Supplementary Table S7). This evidence concerns the gene PPIAL4A and colonic neoplasm.